DC Characterization of AC Current Shunts for Wideband Power Applications

The direct-current (dc) properties of a set of recently developed wideband alternating-current (ac) shunts in the range of 30 mA to 10 A are presented. The characterization includes the long-term drift, the temperature coefficient, and the power coefficient, which all appear to have effects on the level of 1-10 μΩ/Ω. After corrections for these effects, the total uncertainty in the shunt resistance is between 1 and 3 μΩ/Ω. These results prove the suitability of the shunts for wideband power applications where both small ac-dc transfer differences (small phase angles) over the whole frequency range and stable dc characteristics are required.